Fuel burning air and liquid heater



Nov. 4, 1952l c. M. BACKUS 2,616,412

FUEL BURNING AIR AND LIQUID HEATER Filed Jan. 31, 1948 Patented Nov. 4,1952 AUNITED STATES PATENT OFFICE FUEL BURNING AIR AND LIQUID HEATERCharles M. Backus, Burbank, Calif.

Application January 31, 1948, Serial No. 5,541

My invention relates in general to heaters and, more particularly, to aheater of the type in which heat is transferred from one fluid toanother, a primary object of the invention being to provide a heater.having an improved heat exchanging means.

' More specifically, the invention is directed to a, heater'having oneor more substantially vertical coils of tubing through which a fluid tobe heated may flow. f

` A further object is to provide a heater which includes a substantiallyvertical ue positioned above and extending upwardly from a burner, whichincludes concentric inner and outer coils encircling the flue andadapted to convey the fluid to be heated, and which includes a hood overthe coils and the flue, the hood being adapted to deect products ofcombustion ilowing upwardly through the flue from the burner outwardlyand downwardly so as to form an annular stream which flows downwardlybetween the flue and the hood in contact with the'coils. Still anotherobject is to provide a heater wherein the hood,v coils, and flue areencircled by acasing which cooperates with the hood to provide anannular spacev communicating with the space between the hood and theflue so that the products of combustion may flow upwardly through thisannular space after flowing downwardly past the coils. v

important objectof the invention is to provide a heater wherein theinner coil contacts the flue and wherein the outer coil contacts thehood so that heat may be transferred from the products of combustionflowing upwardly through the ueto the fluid in the inner coil byconduction through the walls of the ue, and may be transferred from theproducts of combustion owing upwardly through the annular space betweenthe casing and the hood to the fluid in the outer coil by conductionthrough the walls of the hood. Another important object in thisconnection is to provide a heater wherein .the coils are iiattened toprovide large areas of contact with the walls of the flue and the hood.This construction permits a considerable quantity of heat to betransferred from the products of combustion to the uid in the inner andouter coils by conduction through the walls of the flue and `the hood,which is an important feature ofthe invention.

3 Claims. (Cl. 126-101) Another object is to provide a heater havingmeans for transferring heat to a stream of air flowing through theheater. A related object is to provide a heater having an outer hoodwhich is spaced from the casing to provide a chamber through which airto be heated may be circulated.

Another important object of the invention is to provide a device which,in addition to being capable of heating a iluid flowing through thecoils, is also adapted to be used to cool a uid owing therethrough. l

The foregoing objects of thev invention and the advantages suggestedthereby, together with various other objects and advantages which willbecome evident, may be attained through the utilization of the exemplaryembodiment which is illustrated in the accompanying drawing and which isdescribed in detail hereinafter. Referring to the drawing:

Fig. 1 is a utility view showing an applica-v tion of a heater whichembodies the invention to the cooling system of an automobile engine.

Fig. 2 is a vertical sectional view of the heater;

Fig. 3 is a vertical sectional View of the heater which is taken alongthe broken line 3-3 of Fig. 2; and

Fig. 4 is a transverse sectional view which is taken along the brokenline 4-4 ofFlg. 2 of the drawing.

The heater of my invention, indicated generally in the drawing by thenumeral lll, is susceptible of various applications, one of these beingillustrated in Fig. 1 wherein I show the heater connected to the coolingsystem Il of an automobile engine l'2 for purposes of illustration, theheater being mounted on the re wall I3 of the automobile in which theengine is mounted. In the particular installation illustrated in Fig. 1of the drawing, one of the functions of the heater IB is to maintain thewater or other fluid in the cooling system Il at or near operatingtemperature so as to eliminate anyy necessity for preliminary warm-up ofthe engine after starting same. However, the heater I0 may be employedfor other purposes, such as maintaining the oil of an aircraft engine ator near operating temperature, and it will be understood that I do notintend to be limited to the specic application illustrated in thedraw-,-

Considering the heater Iil in more detail, it includes a vertical,substantially cylindrical casing I5 having an upper end wall I6 and aperipheral wall I1, the lower end of the casing being closed by a baseI8 having an annular flange I9 which telescopes over the casing.Disposed within the casing I5 is a burner 22 which is mounted on acup-shaped bracket 23 carried by the base I8, the burner being suppliedwith fuel, such as gas or gasoline, through a fuel line 24. The burner22 per se forms no part of the present invention and, since any suitableburner may be employed, it is not shown and described in detail.

A member forming an annular chamber 25 having an upper wall 26 and innerand outer walls 21 and 28 is carried by the base I8 and encirclestheburner 22, the inner wall 21 preferably being sealed with respect to theburner, and the inner and outer walls 21 and 28 p'rer^ erably beingsealed with respect to the base, as by welding annular flanges'ZS at thevlower ends of the inner and outer walls to the base. It will be notedthat the inner wall 21 of the annular chamber 25 and the cup-shapedbracket 23 cooperate to dene an annular space3, combustion air beingsupplied to the burner 22 through 'the annular'space 30 and chamber 25by way of openings 3I inthe base I3, openings 32 in the inner wall 21 ofthe chamber and openings 33 in the upper wall 25 of the chamber, asindicated by the arrows 34. With this construction, in the event of aflash-back from the burner 22, any flames are extinguished either in theannular chamber 25, or in the annular spa'ce 35 between the cup-shaped,bracket 23 and the chamber 25, so that 'no llame can escape from thecasing I5, which is an important lfeature of *the invention.

Gases produced by combustion of the fuel supplied to the burner 22 owupwardly from the burner through a flue 3B, as indicated by the arrows39, the combustion zone extending upwardly into the flue so that thelatter may be regarded as a combustion chamber for the fuel Vsupplied tothe burner. The ilueY 38 includes a lower, upwardly converging,truste-conical portion 40 and an upper, cylindrical portionI. The flue38 is centrally located within the casing I5 and is mounted on anannular shroud 42 which extends inwardly from the peripheralwall l1 fthe casing, the shroud `terminating "in an upwardly converging,frusto-conical flange 43 which extends into the frusto-conical portion40 of the ilue, the flue being secured to the shroud by rivets 44 or thelike. The shroud 42 provides a seal between the casing I and the Vflue38 so that all of the products of combustion emanating from the burner22 flow upwardly through the flue.

Disposed within the casing I5 over the flue 38 is a hood 41 having anupper end wall 48 which is spaced from the upper end of the flue andwhich is suitably secured to the upper end wall I5 of the casing, as byspot welding for example. The hood 41 is provided with a downwardlyextending peripheral wall 49 which terminates above the shroud 42 andwhich divides the space between the peripheral wall I1 of the casing I5and the ue 38 into annular spaces 5I and 52. Secured to the upper endWall 48 of the hood 41 is a generally 'conical baille 53 which isaligned with the flue 38 and is spaced from the upper end thereof, thebaille 'being adapted to direct the products of combustion owingupwardly through the flue outwardly and downwardly into the annularspace 5I in the form of an annular stream, as indicated by the arrows54. Subsequently, the products of combustion flow from the annular space5I into the annular space 52 and ow upwardly through the latter into anexhaust tube 55 connected to the casing I5, as indicated by the arrows56. A suitable exhaust line (not shown) connected to the outlet 55 maybe employed to convey the products of combustion to a suitable point ofdisposal, such as the exterior of an automobile, for example, in whichthe heater I5 may be installed. .I t A t 'Concentricy substantiallyvertical inner and outer coils 6I and 62 are disposed in the annularspace 5I between the flue 38 and the peripheral wall 49 of the hood 41,each coil comprising a helical tube through which water from the coolingsystem I I, for example, may flow. The lower ends of the helical tubesforming the coils BI and B2 are interconnected, as by a manifold 63, andthe upper. ends thereof are similarly interconnected, as by a manifold64, the lower ends of the helical tubes being connected to an inlet tube65 which Ais threaded into the Amanifold 63, and the upper ends 'thereofbeing' connected to an outlet `tube 66 which is threaded into themanifold 64, all as best shown in v2rofftl`1e drawing. As indicated inFig: 1 of theidrvawing, the heater may be connected 'in' 'thecooling'system II, for example, ,by lines61 andf68`cone'cted to the inlet 55and outlet 66, respectively., How.- ever, it will be understood that theinvention'is susceptible of various other applications 'as hereinbeforediscussed. ,t

As best shown in Fig. 3, of the drawing, 'the inner coil 6I contacts theflue"38 so that Asome heat' may be transferred from the products ofcombustion owing upwardly ,through 'the'fle to the water or other lfluidin the inner coil by conduction through the walls of thefluveand thetube forming the inner coil. Similarly,the outer coil 62 contacts theAperipheral wall4 '49 of the hood 41 so that some heat from the productsof combustion flowing upwardly through the an? nular space 52 maybetransferred to'thewater or other uid in the `outer, 'coil ,byconduction. In order to increase the quantity of heat transferred to thewater or other fluid by conduction in this manner, theY tubes formingthe inner and outer t coils 6I and 62 are p'refeiablyv flattened, asindicated lby the numerals 4mand 1I. 're-spec#- tively, to increase theareals'ofjconta'ct 'between the inner coil and the flue 38 andlbetwenl'the outer coil and the hood 41, which is'an important feature ofthe invention. I y t o,

Considering the operation of the yheater Illas thus far described, fuel,suchl as gasolinefmay be admitted to the burner 2 2 by opening a valve12 interposed between the fuel' line 2,4 andthe burner and may beignited by energizing a suitable spark-producing device 13, as is wellknown in the art. Air for the combustion of the fuel supplied to thebur-ner 2,2 flows through the ane nular 'space 33 between the cup-shapedbracket 23 and the annular chamber 25 and through the annular chamber25, as indicated by the-arrows 34, the annular space 33 and'chamberV 25preventing any flash-back as Vpreviously discussed. Preferably, theareas of the openings 3'Ij4 32 and 33 'through which the ai-r suppliedtoV theburnfer flows are such that anV excess off'co'ribustion'air issuppl'ied'to the burner toinsure 'cqnipltecombustion of the fuel as iswell'iftheart.

The products of.v4 combustionemanating from the burner 22l flowsupwardly through the flue 38 and'become thoroughly mixed with anylexcess air supplied to the burner so that, by the time the products of`combustion reach the upper end of the flue, the temperature thereof issubstantially uniform. It will be noted that the flue 38 prevents. theproducts of combustion from coming in contact with the coils 6I and 62until such uniform temperature is attained, thus preventing localoverheating of the coils, which is an important feature of theinvention.- As previously discussed, some of the heat contained in theproductsA of combustion owing upwardly through the flue 38 istransferred to the water or other fluid in the inner coil 6I byconduction, the tube forming the inner coil being flattened to increasethe quantity of heat transferred in this manner.

As the products of combustion reach the upper end of the flue 38, theyare directed downwardly and outwardly by the baie 53 and flow downwardlythrough the annular space 5I in contact with the coils 6I and l62,additional quantities of heat being transferred from the products ofcombustion to the fluid in the coils by conduction through the walls ofthe tubes forming the coils. Subsequently, the products of combustion owfrom the annular space 5l into the space 52 and flow upwardly throughthe latter to the exhaust tube 55, as indicated by the arrows 55. Aspreviously discussed, an exhaust line (not shown) leading to a suitablepoint of disposal may be connected to the exhaust tube 55.

As heat is transferred to the fluid in the coils 6I and 62 in thismanner, the iiuid therein circulates upwardly through the coils byconvection. Thus, a countercurrent relationship between the direction offlow of the fluid through the coils '6I and 62 and the direction of owof the products of combustion contacting the coils obtains, which is animportant feature of the invention.

In the particular application of the invention illustrated in thedrawing, water from the cooling system II flows by convection throughthe line 6'I to the heater and returns to the cooling system through theline 68. It will be understood that the water in the cooling system `IImay be maintained at any desired temperature by regulating the amount offuel supplied to the burner 22. When the engine I2 is started, the heatproduced thereby normally will maintain the temperature of the water inthe cooling systern II at the proper operating level and the burner 22may be extinguished.

As previously discussed, an important feature of the invention is toprovide a heater which, in addition to maintaining the temperature of afluid, such as the water in the cooling system I I, at a predeterminedvalue, is also adapted to supply heated air which may be used forheating the passenger compartment of an automobile, for windshielddefrosting, etc. As best shown in Figs. 2 and 3 of the drawing, theheater I0 includes an outer casing I5 which is connected to the casingI5 by bolts 1G, the outer casing being spaced from the casing I5 andbeing sealed with respect thereto. The outer casing 'I5 is provided withan inlet duct I1 having therein a motor 'I8 which is adapted to drive afan 19, and is provided with outlet tubes 80 and 8| to which ducts (notshown) leading to points where heated air is desired may be connected.For example, a duct terminating in the passenger compartment of anautomobile may be connected to the outlet tube 80 and a duct leading toa windshield adapted to heat the fluid circulating through the coils 6Iand 62, which is an important feature of the invention.

As best shown in Figs. 3 and 4 of the drawing, the peripheral wall I1 ofthe inner casing l5 and the peripheral wall 49 of the hood 4'1 areprovided with openings 84 and 85, respectively, which are aligned withthe inlet duct 11, the openings 84 and 85 normally being closed bycurved shutters 86 and 81 which are movable in suitable tracks 88 andwhich may be opened manually by a handle 89 connected thereto. It willbe apparent that when the shutters and 8I are opened, the fan 'I9 may beemployed to circulate air through the annular space 5I containing thecoils 6I and 62, such air escaping through the exhaust tube 55. Thisfeature of the invention is important in that it permits the fan 'I9 tobe used to circulate air for reducing the temperature of the water orother iiuid in the coils 6| and 62 to reduce the temperature of thecooling system II, for example, if' the engine I2 tends to overheat inhot weather. Since the air heated in this manner escapes through theexhaust tube 55, which, as previously discussed, may be connected to asuitable point of disposal, it is not discharged into the interior ofthe automobile.

Although I have disclosed an exemplary embodiment of my invention andhave described a specific application thereof for purposes of illustration, it will be understood that I do not intend to be limitedthereto since the invention is susceptible of various other applicationsand since various changes, modifications and substitutions may beincorporated in the exemplary embodiment disclosed, all withoutnecessarily departing from the spirit of the invention. Consequently, Ihereby reserve the right to the protection afforded by the full scope ofthe appended claims.

I claim as my invention:

1. In a heater, the combination of: a burner; a substantially verticaliiue positioned above and extending upwardly from said burner; asubstantially vertical coil comprising a helical tube which encirclessaid flue, said tube having an inlet at one end for a fluid to be heatedand having an outlet at its other end for heated fluid; a hood over saidflue and said coil, said hood comprising an end wall which is spacedfrom the upper end of said flue and comprising a downwardly extendingperipheral wall which encircles said coil and said ilue; an inner casingenclosing said hood and having a peripheral wall which is concentricwith and spaced from said peripheral wall of said hood, said innercasing being provided with an outlet adjacent its upper end whichcommunicates with the space between said peripheral walls; and an outercasing over said inner casing, said outer casing being spaced from saidinner casing and being provided with an inlet and an outlet whichcommunicate with the space between said casings.

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eralwu''f sid'in'er casing are provid-ed*y with im@ d thispatem:

M, BAGKUS, 507,113 f Marshall May '9:1950

